CHARACTERISTICS OF THE EXTRACELLULAR MATRIX OF ADIPOSE STROMAL PROGENITOR CELLS AFTER A LONG-TERM SIMULATION OF MICROGRAVITY

Effects of 21-day microgravity simulated by the random positioning machine (Gravite) on the functional activity of mesenchymal stromal cells (MSCs) from the human adipose tissue (cytokine profile, expression of genes and surface markers) and ability to produce the extracellular matrix (ECM) were investigated. It has been found that after the long-term exposure in microgravity MSCs persevered high viability and stromal phenotype. Changes in expression of the surface adhesion molecules consisted in an increase of integrin CD49 and decrease of endoglin CD105. The cytokine profile was shifted, i.e. VEGF concentration increased, while concentrations of IL-6, G-CSF and eotaxin decreased. Expression of the metalloproteinase 1 (MMP1) gene downregulated and that of matrix protein osteopontin SSP1 upregulated. Structural proteins osteopontin, fibronectin and collagen were equally well visualized in all the experimental groups. These findings point to the MSCs functional retention and ECM adaptive shifts in response to the long-term exposure in simulated microgravity.